The external high-speed electro-optic modulator is a necessary device for varieties of optical communication systems, where the direct modulation of the laser is not applicable due to either operation speed limitation or the frequency chirp or poor signal integrality causing unbearable impairment during the transmission.
Being able to fabricate the electro-optic modulator on silicon using standard VLSI process possesses the advantages of low-cost and easy integration with electronics. Recently, extensive efforts of developing electro-optic modulator on silicon have been taken, and lots of breakthrough development. The published works include forward biased PIN diode structure[1][2] and metal-on-semiconductor (MOS) capacitance structure[3], which was able to demonstrate 1 Gbps operation speed. The inventor of this patent has made the most critical original contribution to this field, and successfully demonstrated the first 10 Gbps silicon EO modulator fabricated standard CMOS process. The attached patent documents[4-6] present part of the silicon modulator technologies that the inventor have developed in the past.    1. P. D. Hewitt and G. T. Reed, “Improved modulation performance of a silicon p-i-n device by trench isolation,” J. of Lightwave Technology, Vol. 19, No. 3, pp 387-390, March 2001.    2. Giuseppe Coppola, Andrea Irace, Mario Iodice, Antonello Cutolo, “Simulation and analysis of a high-efficiency silicon optoelectronic modulator based on a Bragg mirror,” Opt. Eng. 40(6), 1076-1082 (June 2001).    3. “A high speed silicon optical modulator based on metal-oxide-semiconductor capacitor”. Nature, vol. 427, 2004, page 615-618.    4. Integrated optical and electronic devices (CMOS Optics). Luxtera Inc., application Ser. No. 10/606,297.    5. Active waveguides for optoelectronic devices. Luxtera Inc., application Ser. No. 10/650,234.    6. High-speed electro-optic modulator on silicon SOI using periodical distributed lateral abrupt PN diode structure. Luxtera Inc., provisional application No. 60/495,402.